Quasi-elastic scattering for the nuclear ground state structure: An intriguing case of $^{30}$Si
nucl-ex
/ Authors
Y. K. Gupta, B. Maheshwari, G. K. Prajapati, A. K. Jain, K. Hagino, B. N. Joshi, A. Pal, N. Sirswal, Pawan Singh, S. Dubey
and 10 more authors
V. V. Desai, V. Ranga, V. B. Katariya, D. Patel, H. Vyas, S. Panwar, B. V. John, I. Mazumdar, B. K. Nayak, U. Garg
/ Abstract
Quasi-elastic (QEL) scattering measurements have been performed using the $^{28, 30}$Si projectiles off the $^{90}$Zr target at energies around the Coulomb barrier. Coupled-channels (CC) calculations were carried out in a large parameter space of quadrupole and hexadecapole deformations for the N=Z, $^{28}$Si and N=Z+2, $^{30}$Si nuclei. $^{28}$Si at the N=Z line is observed to be uniquely oblate shaped in its ground state. In contrast, for $^{30}$Si with just two additional neutrons -- oblate, prolate, and spherical CC descriptions are equally compatible with the measurements. To further investigate the nuclear structure evolution with varying neutron number, shell-model calculations were performed. These calculations reveal a sudden change in the nuclear structure aspects at $^{30}$Si in going from $^{28}$Si to $^{30}$Si. Combined reaction and structure analyses consistently indicate that $^{30}$Si does not possess a well-defined intrinsic shape, and it is a potential candidate for ``shape fluctuations" in its ground state.